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An Economical Digitally Controlled Audio Level Indicator

The design of an accurate, inexpensive, compact, easy to read audio program level indicator has always been plagued by compromises. The best of the previous designs used light-emitting diodes (LED) in a bar-graph arrangement driven by digital logic. An improved method of driving the LED displays is described which is considerably cheaper and simpler than previous designs. The circuit design, operation, and performance are discussed.